A urokinase-type plasminogen activator deficiency diminishes the frequency of intestinal adenomas in ApcMin/+ mice.

The interaction of urokinase-type plasminogen activator (uPA) and its receptor, uPAR, on cell surfaces facilitates the generation of cell-bound plasmin, thus allowing cells to establish a proteolytic front that enables their migration through protein barriers. This complex also activates cell signalling pathways that influence cell functions. Clinical studies have identified uPA as an indicator of poor overall survival in patients with colorectal cancer. In the current study, a mouse model of colon cancer, Apc(Min/+), with an additional deficiency of uPA (Apc(Min/+)/Plau-/-) was used to determine the effects of uPA on tumour initiation and growth. Utilizing this model, it was found that the number of tumours was diminished in these mice relative to Apc(Min/+) mice, which correlated with the decreased leukocyte infiltration in the tumours. However, tumour growth was not impeded in Apc(Min/+)/Plau-/- mice, and proliferation and tumour vascularization were, in fact, enhanced in Apc(Min/+)/Plau-/- mice. These latter effects are consistent with a mechanism involving up-regulation of COX-2 expression and Akt pathway activation in Apc(Min/+)/Plau-/- mice. The results from this study suggest that uPA plays dual and opposing roles in regulating lesion development: one early, during the transition from normal epithelia to dysplastic lesions, and another later during tumour growth.

Design of flow chamber with electronic cell volume capability and light detection optics for multilaser flow cytometry.

A multibeam optical detection system has been developed with a high optical efficiency, achieved through a reduction in the number of optical interfaces employed in the system. This reduction is made possible by a combination of employing simple lenses, gluing the objective lens directly upon the face of the flow cuvette and the extraction of only one fluorescence signal from each laser beam. A modified flow chamber is also described that includes fluidic resistance elements for the elimination of most of the electric shielding normally associated with electronic cell volume measurements.

The effect of ultrasonics and thermal treatment on wounds.

A method of local treatment of wounds to accelerate healing would be a major benefit in those patients in whom abnormal healing is expected. Earlier studies has suggested that local ultrasonic treatment of wounds would stimulate the healing process. We have evaluated the effect of local ultrasound (5 MHz) and thermal treatments on healing in a dermal wound model. Various intensities of ultrasound and heat were employed for 5 min/day (0.05 W/cm2) and 10 min/day (0.05W/cm2), with healing assessed by wound breaking strength measurements obtained 14 days after injury. Subcutaneous temperature measurements demonstrated that equal intensities of ultrasound and heat produced equivalent temperature changes in the tissues. None of the treatments employed resulted in greater wound breaking strengths than the controls, and the higher intensities of ultrasound (0.1 and 0.15 W/cm2) and heat (0.15 W/cm2) resulted in decreased wound breaking strength. Our results failed to support brief daily treatments of local ultrasound or heat as stimulants of wound healing.

Rapid entry port for an anaerobic glove box.

A rapid entry mechanism for an anaerobic glove box is described. The entry port is practical for entry or removal of one or two items and requires only seconds to operate. No deleterious effect on isolation or growth of anaerobes has been encountered since installation of the rapid entry port 3.5 years ago. Details for its construction are given.